Constant velocity universal joints (CVJ) are known in the art, as illustrated by commonly assigned U.S. Pat. No.4,840,600 to White et al., and the patents cited therein. As noted in the aforementioned commonly assigned U.S. patent, CVJs are used, for instance, in the transaxle of the front wheel drive system of a motor vehicle in which the engine transfers power through a transmission to the front wheels of the vehicle. In the aforementioned patent, as illustrated particularly in FIGS. 3-4 of that patent, one type of known CVJ utilizes a three-lobed housing, in which an inner rotatable member has three equi-angularly spaced, radially extending trunnions, each of which extends into one of the three lobes of the housing. Each trunnion supports a spherical ball and socket assembly positioned intermediate the trunnion and the housing to provide universal movement of the trunnion within the housing. Recirculating needle bearings are arranged between the socket and the housing to provide substantially frictionless axial movement between the housing and the rotatable member. This CVJ may be characterized as a recirculating needle CVJ.
Other similar CVJs are illustrated in each of U.S. Pat. Nos. 4,192,154 to Nakamora et al; 4,684,356 to Kamata et al; and 4,580,995 to Orain, each of which is cited in the aforementioned U.S. Pat. No. 4,840,600 to White et al.
In the known constructions and in the art in general a deficiency exists in the CVJ. In most known constant velocity joints, at the interface between the outer surface of the trunnion and the inner surface of the ball member disposed between the trunnion and the housing, there is sliding friction contact between the ball member and the trunnion. Of the known CVJs, only that of the aforementioned Orain patent discloses an antifriction bearing positioned at the aforesaid interface. However, the antifriction bearing disclosed in the Orain patent facilitates only frictionless movement of the trunnion with respect to the ball member in a direction parallel to the sliding axis of the CVJ. In the axial direction of movement between the ball member and the trunnion, a sliding friction interface still exists. At this sliding friction interface, the possibility exists for a "slip-stick" motion of the ball member as it translates axially relative to the trunnion. This slip-stick motion may create a roughness in the CVJ, which translates into a roughness or shudder potential in the automotive vehicle during operation.
It would be desirable, therefore, to reduce or eliminate entirely this potential slip-stick motion in a CVJ, as well as other potential vibration or resonance-inducing motions of the CVJ.